In a typical cellular network, also referred to as a wireless communication system, User Equipments (UEs), communicate with a radio network node, in a Radio Access Network (RAN).
A user equipment is a mobile terminal by which a subscriber may access services offered by an operator's core network and services outside operator's network to which the operator's RAN and CN provide access. The user equipments may be for example communication devices such as mobile telephones, cellular telephones, or laptops with wireless capability. The user equipments may be portable, pocket-storable, hand-held, computer-comprised, or vehicle-mounted mobile devices, enabled to communicate voice and/or data, via the radio access network, with another entity, such as another mobile station or a server. User equipments are enabled to communicate wirelessly in the cellular network. The communication may be performed e.g. between two user equipments, between a user equipment and a regular telephone and/or between the user equipment and a server via the radio access network and possibly one or more core networks, comprised within the cellular network.
The radio access network covers a geographical area which is divided into cell areas, with each cell area being served by a Base Station (BS), e.g. a Radio Base Station (RBS), which in some radio access networks is also called evolved NodeB (eNB), NodeB, or radio base station. A cell is a geographical area where radio coverage is provided by the radio base station at a base station site. Each cell is identified by an identity within the local radio area, which is broadcasted in the cell. The base stations communicate over the air interface operating on radio frequencies with the user equipments within coverage range of the base stations.
In some versions of the radio access network, several base stations are typically connected, e.g. by landlines or microwave, to a Radio Network Controller (RNC), as in third Generation (3G), i.e. Wideband Code Division Multiple Access (WCDMA). The radio network controller supervises and coordinates various activities of the plural base stations connected thereto. In second Generation (2G), i.e. Global System for Mobile Communications (GSM), the base stations are connected to a Base Station Controller (BSC). The network controllers are typically connected to one or more core networks.
Some nodes in the communications network may also be equipped with user equipment-like interface, e.g., to be able to receive downlink signals.
The possibility of identifying a user equipments geographical location in a wireless cellular communication network has enabled a large variety of commercial and non-commercial services, e.g., navigation assistance, social networking, location-aware advertising, emergency calls, etc. Different services may have different positioning accuracy requirements imposed by the application. In addition, some regulatory requirements on the positioning accuracy for basic emergency services exist in some countries.
In many environments, the position of a user equipment may be accurately estimated by using positioning methods based on the Global Positioning System (GPS). Nowadays, networks also often may assist user equipments in order to improve the user equipment, or terminal, receiver sensitivity and GPS start-up performance, i.e. Assisted-GPS positioning (A-GPS). GPS receivers or A-GPS receivers, however, may not necessarily be available in all wireless user equipments. Furthermore, GPS is known to fail often in indoor environments and urban canyons. A complementary terrestrial positioning method, called Observed Time Difference of Arrival (OTDOA), has therefore been standardized by the Third Generation Partnership Project (3GPP). In addition to OTDOA, the Long Term Evolution (LTE) cellular standard also specifies methods, procedures, and signaling support for Enhanced Cell ID (E-CID) and Assisted Global Navigation Satellite System (A-GNSS) positioning. Later, Uplink TDOA (UTDOA) may also be standardized for LTE.
With E-CID positioning, the following sources of position information may be involved: the Cell Identification (CID) and corresponding geographical description of a serving cell, the Timing Advance (TA) of the serving cell, and the CIDs and corresponding signal measurements of the cells, e.g. up to 32 cells in LTE, including the serving cell, as well as Angle-of-Arrival (AoA) measurements. The following user equipment measurements may be utilized for E-CID in LTE: Evolved Universal Terrestrial Radio Access (E-UTRA) carrier Received Signal Strength Indicator (RSSI), Reference Signal Received Power (RSRP), Reference Signal Received Quality (RSRQ), and UE receive-transmit (Rx-Tx) time difference. The E-UTRA network (E-UTRAN) measurements available for E-CID include eNodeB Rx-Tx time difference, also called TA Type 2; TA Type 1, being (eNodeB Rx-Tx time difference)+(UE Rx-Tx time difference); and uplink (UL) AoA. UE Rx-Tx measurements are typically used for the serving cell, and for example RSRP and RSRQ as well AoA may be utilized for any cell and may also be conducted on a frequency different from that of the serving cell.
User equipment E-CID measurements are reported by the user equipment to a positioning server, e.g., an Enhanced Serving Mobile Location Centre (E-SMLC) or Secure User Plane Location (SUPL) Platform (SLP) in LTE, over the LTE Positioning Protocol (LPP), and the E-UTRAN E-CID measurements are reported by the eNodeB to the positioning node over the LPP Annex protocol (LPPa). Some measurements, e.g. UE Rx-Tx, may also be reported to the eNodeB for some measurement configurations.
With OTDOA positioning, a user equipment measures the timing differences for DownLink (DL) reference signals received from multiple distinct locations. For each, e.g. measured, neighbor cell, the user equipment measures Reference Signal Time Difference (RSTD) which is the relative timing difference between neighbor cell and the reference cell. The user equipment position estimate is then found as the intersection of hyperbolas corresponding to the measured RSTDs. At least three measurements from geographically dispersed base stations with a good geometry are needed to solve for two coordinates of the user equipment and the receiver clock bias. In order to solve for position, precise knowledge of the transmitter locations and transmit timing offset is needed. Position calculation may be conducted, for example, by a positioning server, e.g., E-SMLC or SLP in LTE, or the user equipment. The former approach corresponds to the UE-assisted positioning mode, whilst the latter corresponds to the UE-based positioning mode.
To enable positioning in LTE and facilitate positioning measurements of a proper quality and for a sufficient number of distinct locations, new physical signals dedicated for positioning, e.g. positioning reference signals, or Position Reference Signal (PRS), have been introduced and low-interference positioning subframes have been specified in, for example, 3GPP Technical Specifications.
PRS are transmitted from one antenna port, e.g. R6, according to a pre-defined pattern. A frequency shift, which is a function of Physical Cell Identity (PCI), may be applied to the specified PRS patterns to generate orthogonal patterns and modeling the effective frequency reuse of six, which makes it possible to significantly reduce neighbor cell interference on the measured PRS and thus improve positioning measurements. Even though PRS have been specifically designed for positioning measurements and in general are characterized by better signal quality than other reference signals, the standard does not mandate using PRS. Other reference signals, e.g., Cell-specific Reference Signals (CRS), may be used for positioning measurements.
PRS are transmitted in pre-defined positioning subframes grouped by several consecutive subframes, e.g. N_PRS, i.e. one positioning occasion. Positioning occasions occur with a periodicity of N subframes, i.e., the time interval between two positioning occasions. The standardized periods N are 160, 320, 640, and 1280 milliseconds (ms), and the number of consecutive subframes is 1, 2, 4, and 6.
Since for OTDOA positioning PRS signals from multiple distinct locations need to be measured, the user equipment receiver may have to deal with PRS that are much weaker than those received from the serving cell. Furthermore, without approximate knowledge of when the measured signals are expected to arrive in time and what is the exact PRS pattern, the user equipment would need to do signal search within a large window which would impact the time and accuracy of the measurements as well as the user equipment complexity. To facilitate user equipment measurements, the network, e.g. a positioning node such as e.g. the E-SMLC or SLP, transmits assistance data to the user equipment. The assistance data comprises, among the other things, reference cell information, a neighbor cell list containing PCIs of neighbor cells, the number of consecutive downlink subframes, PRS transmission bandwidth, frequency, etc.
The may be restrictions on the number of frequencies in the assistance data. A restriction may be that, in LPP, for the neighbor cell list, the cells comprised in the neighbor cell list in the assistance data may be at most on three different frequencies, controlled by maxFreqLayers parameter, currently set to 3, excluding the reference cell frequency. Another restriction may be that, for inter-frequency RSTD requirements, the 3GPP specifies inter-frequency RSTD requirements that apply for two frequencies which are the serving cell frequency and the measured cell frequency.
OTDOA and other positioning methods, such as E-CID, are to be used also for emergency calls. Hence, the response time of these measurements should be as low as possible to meet the emergency call requirements. Therefore, it is important to define how the requirements apply when more than one inter-frequency are present in the cell list of the assistance data and which cells are to be included in the neighbor cell list to account for the maxFreqLayers restriction. Note also that the frequency supported by the user equipment/positioning target may or may not be known in the node creating assistance data e.g., the positioning server E-SMLC or SLP in LTE.
Furthermore, one shall note that the cell, e.g. reference and neighbor, information in the RSTD assistance data is optional and it is not explicitly stated what shall be assumed when the reference cell is missing in the assistance data. The reference cell information is used when defining muting configuration, slotNumberOffset and expectedRSTD, which may be defined differently for intra- and inter-frequency, which is important to know since these parameters may also be used for defining parameters for neighbor cells. This indicates the importance of knowing at least the reference cell and the serving cell frequencies.
For LTE Time Division Duplex (TDD), the same positioning measurement definition, the same methods and the same accuracy requirements shall apply as for Frequency Division Duplex (FDD). For intra-frequency RSTD measurement requirements with the smallest reference signal measurement bandwidths as well as for inter-frequency RSTD measurement requirements, not all uplink-downlink subframe configurations are applicable.
To define whether intra- or inter-frequency or inter-Radio Access Technology (RAT) requirements apply, the serving cell frequency and the serving cell RAT information, shall be taken into account e.g. when configuring assistance data.
Inter-frequency measurements may in principle be considered for any positioning method, even though currently not all measurements are specified by the standard as intra- and inter-frequency measurements.
The current standard specifies the minimum number of inter-frequencies the user equipment shall be capable of measuring on, which defines the minimum mandatory user equipment measurement capability. Furthermore, such capability is currently only specified for each duplex mode separately. For example, 3GPP specifies that the user equipment shall be capable of performing RSRP and RSRQ measurements, which are a part of e.g. E-CID, of at least 4 inter-frequency cells per FDD inter-frequency for up to 3 FDD inter-frequencies. Further, the user equipment physical layer shall be capable of reporting RSRP and RSRQ measurements to higher layers with a predefined measurement period. The user equipment shall also be capable of performing RSRP and RSRQ measurements of at least 4 inter-frequency cells per TDD inter-frequency for up to 3 TDD inter-frequencies. The user equipment physical layer shall also be capable of reporting RSRP and RSRQ measurements to higher layers with a predefined measurement period.
There are requirements on the number of frequencies monitored by the user equipment for E-UTRA. The number of frequencies may be dependent on the UE capability, e.g. 3 FDD E-UTRA inter-frequency carriers or 3 TDD E-UTRA inter-frequency carriers. Similar requirements also exist for other RATs.
The user equipment performs inter-frequency measurements in measurement gaps. The measurements are done for various purposes: mobility, positioning, Self Organizing Network (SON), Minimization of Drive Tests (MDT), etc. Furthermore, the same gap pattern is used for all types of inter-frequency and inter-Radio Access Technology (inter-RAT) measurements. Therefore E-UTRAN must provide a single measurement gap pattern with constant gap duration for concurrent monitoring, i.e., cell detection and measurements, of all frequency layers and RATs. The E-UTRA user equipment supports two configurations comprising of the Maximum Gap Repetition Period (MGRP) of 40 ms and 80 ms; both with the measurement gap length of 6 ms. In practice due to the frequency switching time, fewer than 6 sub-frames but at least 5 full sub-frames are available for measurements within each such measurement gap.
In LTE, measurement gaps are configured by the network to enable measurements on the other LTE frequencies and/or other RATs, e.g. UTRA, GSM, Wideband Code Division Multiple Access 2000 (CDMA2000), etc. The gap configuration is signaled to the user equipment over the RRC protocol as part of the measurement configuration. Only one gap pattern may be configured at a time. The same pattern is used for all types of configured measurements, e.g. inter-frequency neighbor cell measurements, inter-frequency positioning measurements, inter-RAT neighbor cell measurements, inter-RAT positioning measurements, e.g. potentially, etc.
In general, in LTE inter-RAT measurements are typically defined similar to inter-frequency measurements, e.g., they may also require configuring measurement gaps like for inter-frequency measurements, but just with more measurements restrictions and often more relaxed requirements for inter-RAT measurements.
For positioning, assuming that LTE FDD and LTE TDD are treated as different RATs, the current standard defines requirements only for FDD-TDD and TDD-FDD inter-frequency measurements, and the requirements are different in the two cases. There are no other inter-RAT measurements specified within any separate RAT for the purpose of positioning and which are possible to report to the positioning node, e.g., an E-SMLC in LTE.
In order to meet the performance requirements of Internet Protocol Multimedia subsystem Telephony-Advanced (IMT-Advanced) systems, a concept known as Carrier Aggregation (CA) has been proposed to aggregate two or more component carriers for supporting high data rate transmissions over a wide bandwidth, i.e., up to a 100 MegaHertz (MHz) for a single user equipment unit, while preserving backward compatibility with legacy systems. The carrier aggregation is also called, e.g., interchangeably called, “multi-carrier system”, “multi-carrier operation”, “multi-carrier” transmission and/or reception. The Component Carrier (CC) means an individual carrier in a multi-carrier system. One of the CCs is the primary carrier or anchor carrier and the remaining ones are called secondary or supplementary carriers.
Typically the component carriers in carrier aggregation belong to the same technology. E.g. either all are of WCDMA or LTE systems. However the carrier aggregation between carriers of different technologies is also possible to increase the throughput. Using carrier aggregation between carriers of different technologies is also referred to as “multi-RAT carrier aggregation” or “multi-RAT-multi-carrier system” or simply “inter-RAT carrier aggregation”. For example, in such systems one CC may belong to LTE FDD and another one to LTE TDD. Yet another example comprises of CCs belonging to UTRAN FDD and E-UTRAN FDD. Another example is the aggregation of LTE and CDMA2000 carriers. The inter-RAT CA system may even comprise of component carriers belonging to more than two RATs. In such systems one of the RATs may be considered as the main or primary RAT while the remaining ones as the auxiliary RATs.
For the sake of clarity the carrier aggregation within the same technology may be regarded as ‘intra-RAT’ or simply ‘single RAT’ carrier aggregation.
The carrier frequencies in a frequency band are enumerated. The enumeration is standardized such that the combination of the frequency band and the carrier frequency may be determined by a unique number called absolute radio frequency number. A carrier frequency is a term used to designate the nominal frequency of a carrier wave. Multiple carriers may be configured within a frequency band.
In a GSM system, UTRAN, and E-UTRAN, the channel numbers are respectively called:                Absolute Radio Frequency Channel Number (ARFCN),        UTRA Absolute Radio Frequency Channel Number (UARFCN), and        E-UTRA Absolute Radio Frequency Channel Number (EARFCN).        
In FDD systems separate channel numbers are specified for UL and DL. In TDD there is only one channel number since the same frequency is used in both directions.
The channel numbers, e.g., Evolved Absolute Radio Frequency Channel Numbers (EARFCN), for each band are unique to distinguish between different bands. The channel number for each band may be derived from the expressions and mapping tables defined in the relevant specifications. Based on the signaled channel numbers, e.g., EARFCN in E-UTRAN, and the pre-defined parameters associated with each band the user equipment may determine the actual carrier frequency in MHz and the corresponding frequency band. This is explained by the following example.
The relation between the EARFCN and the carrier frequency, F_DL, in MHz for the downlink is pre-defined by the following equation:F_DL=F_DL_low+0.1(N_DL−N_Offs-DL)  Equation 1where F_DL_low and N_Offs-DL are pre-defined values in equation 1 for each band and N_DL is the downlink EARFCN.
Consider E-UTRA band 5, whose EARFNC range, e.g. N_DL, as pre-defined in equation 1 lays between 2400-2649. The pre-defined values of F_DL_low and N_Offs-DL are 869 and 2400 respectively. Assume that the network signals downlink EARFCN to be 2500. Using the above expression the user equipment may determine that the downlink carrier frequency of the channel is 879 MHz.
The LTE specifications enable FDD and TDD operation modes. Additionally, half-duplex operation is also specified, which is substantially FDD operation mode but with transmission and receptions not occurring simultaneously, as in TDD. Half-duplex mode has advantages with some frequency arrangements where the duplex filter may be unreasonable, resulting in high cost and high power consumption. Since the carrier frequency number, i.e. EARFCN, is unique, it is possible to determine the frequency band, which is either FDD or TDD, when the frequency number is known. However, it may be more difficult to find the difference between full-duplex FDD and Half-Duplex FDD (HD-FDD) without explicit information since the same FDD band can be used as full FDD or HD-FDD.
General user equipment radio access capabilities are defined in 3GPP. Some of the user equipment positioning capability information may be transferred from the Mobility Management Entity (MME) to the positioning node over the SLs interface. Other user equipment positioning capability information may be transferred from the user equipment to the positioning node over the LPP protocol.
With the current standard, as explained below, the UE capability information that may be obtained over the SLs and with LPP is very limited, and the general user equipment radio access capabilities may not be transferred to the positioning node at all.
The UE radio access capability parameters currently specified in 3GPP comprise:                ue-Category        Radio Frequency (RF) parameters:                    supportedBandListEUTRA—this field defines which E-UTRA radio frequency bands are supported by the user equipment. For each band, support for either only half duplex operation, or full duplex operation is indicated. For TDD, the half-duplex indication is not applicable.                        Measurement parameters:                    interFreqNeedForGaps and interRAT-NeedForGaps—these fields define for each supported E-UTRA band whether measurement gaps are required to perform measurements on each other supported E-UTRA radio frequency band and on each supported RAT/band combination.                        Inter-RAT parameters:                    These parameters are used, e.g., for indication the supported band lists for UTRA FDD, UTRA TDD, GSM Enhanced Data rates for GSM Evolution (EDGE) Radio Access Network (GERAN).                        General parameters:                    accessStratumRelease—this field defines the release of the E-UTRA layer 1, 2, and 3 specifications supported by the user equipment, e.g., Release 8 (Rel-8), Release 9 (Rel-9), etc.            device Type—this field defines whether the device does not benefit from NW-based battery consumption optimization.                        CSG Proximity Indication parameters: intraFreqProximityIndication, interFreqProximityIndication and utran-ProximityIndication        Neighbour cell SI acquisition parameters: intraFreqSI-AcquisitionForHO, interFreqSI-AcquisitionForHO, utran-SI-AcquisitionForHO        
The parameters are signaled as defined in 3GPP according to which the UE radio access capabilities transfer is initiated by E-UTRAN for a user equipment in RRC_CONNECTED mode when the network needs, e.g. additional, UE radio access capability information. If the user equipment has changed its E-UTRAN radio access capabilities, the user equipment shall request higher layers to initiate the necessary NAS procedures as specified by 3GPP that would result in the update of UE radio access capabilities using a new RRC connection. The UE Radio Capability is not provided directly from one CN node to another. It will be uploaded to the MME when the E-UTRAN requests the UE Radio Capability information from the user equipment.
The UE capability may be transferred over the SLs interface. SLs is the interface between the MME and the positioning node, e.g. the E-SMLC. The interface is used to convey LCS Application Protocol (LCS-AP) messages between these two nodes. The initiator, e.g. the MME, of the location service request procedure sends a Location Request (LR) message to E-SMLC for the target user equipment and starts the timer T3x01. Among the other things, the message comprises an optional element “UE Positioning Capability (O)”. When the UE capability is unknown, the E-SMLC may request UE position capability through LPP.
The UE positioning capability provides information about the LCS capabilities of the target UE and comprises only a single information element, LPP Support, which is a mandatory binary indicator. TRUE means the LPP is supported by the user equipment.
Capability transfer in the LTE positioning architecture is supported in the LPP. The LPP capability transfer procedure comprises a request, e.g. RequestCapabilities, sent from the server to the target, and a response, e.g. ProvideCapabilities, sent from the target to the requesting serve. The LPP capability further comprises an indication procedure used by the target to provide unsolicited capabilities to the server. In both cases, the capability is transferred from a target to a server, where in the 3GPP EPS Control Plane solution typically the user equipment is the target device and the E-SMLC is the server. However, the target device may also be any radio node being positioned, e.g., small radio base station, relay, etc. For SUPL 2.0 support, the SUPL Enabled Terminal (SET) is the target device and the SLP is the server.
LPP procedures are not required to occur in any fixed order, e.g., the target device may transfer capability information to the server, i.e. the positioning server such as, E-SMLC or SLP, at any time if not already performed. The target device may be a UE, a small BS, relay, femto BS, etc. When a target device receives a RequestCapabilities message, it may include the device capabilities for each method included in the request for capabilities and deliver the response to the lower layers for transmission. If the message type is an LPP RequestCapabilities and some of the requested information is not supported, the target returns any information that may be provided in a positioning response.
The requestCapabilities comprises the capabilities for A-GNSS, OTDOA, ECID, as well as common capabilities and epdu capabilities. The OTDOA and ECID requestCapabilities information elements are currently defined as empty sequences. The commonIEsRequestCapabilities information element is provided for future extensibility. The epdu-RequestCapabilities are defined as an EPDU-Sequence comprising information elements that are defined externally to LPP by other organizations.
ProvideCapabilities has a similar structure to that of RequestCapabilities. In the current standard, for OTDOA, the target node may inform the server about the supported positioning mode. Only UE assisted positioning is supported so far. For E-CID, the target informs about the supported E-CID measurements, e.g., RSRP, RSRQ, and UE receive-transmit time difference.
In LPP, at most three different frequencies may be included in the neighbor cell list, excluding the reference cell, and where the neighbor cell list may or may not include the serving cell. At least the following related issues have been identified. There is no mechanism in the positioning node to choose cells for including in the assistance data when cells on several frequencies are available. The positioning server needs to know the frequencies and RATs that may be used or preferred by the user equipment for transmitting positioning measurements to.
The set of frequency layers that may be monitored by the user equipment at the same time is limited, although these layers may be monitored also for other purpose than positioning and thus fewer frequencies may be available for positioning measurements. For example, with the maximum number of monitored frequency layers in measurement gaps equal to 7, the following example measurements configurations may be envisioned:                3 LTE FDD inter-frequencies+1 LTE TDD inter-frequency+2 WCDMA layers+1 GSM.        2 LTE FDD inter-frequencies+2 LTE TDD inter-frequency+3 GSM.        
The current RSTD measurement requirements specified in 3GPP are defined only for two carrier frequencies, being the serving-cell frequency and the neighbor-cell frequency, which may several problems. There is no mechanism in the positioning node to account for this in the assistance data build up. The user equipment may receive a neighbor cell list implying more than the two allowed frequencies and there is no rule specifying to which frequencies the current requirements shall apply at the user equipment side. For instance the user equipment supporting more than two carrier frequencies which are also included in the neighbor cell list, may choose any two of these frequencies for performing inter-frequency RSTD measurements. Since the user equipment behavior of selecting the frequencies when more than 2 frequencies are signaled is not specified, hence there is a risk that the user equipment may choose e.g. not to perform the inter-frequency RSTD measurements at all on one of the frequencies. These unspecified user equipment behaviors are undesirable from the network performance point of view.
The positioning node supports only E-UTRAN measurements. At t the same time, LPP allows for a reference cell to operate on a frequency different than the serving cell. As a result, some of the possible issues are that a reference cell in the neighbor cell list may not be on the serving-cell frequency and the requirements thus may not apply. Furthermore, the positioning node does not know exactly whether the user equipment has to perform inter-frequency measurements. This may impact the assistance data build up, i.e. the inter-frequency measurements may take longer time for the user equipment to measure and be less accurate, the applicability of the RSTD requirements and/or the measurement gap configuration when the latter is triggered or involves the positioning node.
The positioning node is currently not aware of the duplex mode of the cell i.e. whether a cell is an FDD, half duplex FDD (HD-FDD) or TDD cell. In some embodiments, there may be a mix of them in the system.
The positioning node is also not aware of the duplex operation of terminals. Also, the system is not aware of the configuration of TDD cells, whilst some cells may use TDD uplink-downlink subframe configurations for which RSTD requirements do not apply.
Furthermore, the user equipment needs to know the duplex mode of the cell, i.e. whether a cell is FDD, HD-FDD or TDD, in order to correctly apply PRS configuration defined in 3GPP, which specifies the number of consecutive DL subframes, e.g. only DL subframes are counted, which is also assumed to be known when it comes to RSTD requirements.
The radio node, e.g., an eNodeB, capabilities are not defined by the standard and so far may only be provided to the positioning node by a Operations & Maintenance (O&M) node or by locally configuring the positioning node. One of problems that may arise is that there is no standardized interface and corresponding signaling defined to communicate radio node capabilities to the positioning node. Furthermore, different radio nodes, e.g. eNode B or any BS, may differ in terms of their capabilities e.g. in terms of supported frequency bands, hardware capability, bandwidths supported in certain frequency band, transmit power level, receiver type etc. A very large number of radio nodes may be under the influence of the same positioning node for the purpose of positioning. It is very cumbersome for an operator to provide the radio node capability and associated information to the positioning node by manual means such as via O&M. The manual configuration task may become even more tedious in case the radio nodes belong to different manufactures. In addition, there is no mechanism in the positioning node to account for these capabilities in the assistance data build up.